STONY BROOK, NY –While burn pits have been the focus of a controversy for years about causes of high rates of respiratory illnesses among military personnel deployed to Iraq and Afghanistan, evidence increasingly paints a more complex — and far more difficult to address — picture.

Anthony Szema, MD, chief of the allergy section of the VA Medical Center in Northport, NY

At a symposium last month about lung health after deployment to Iraq and Afghanistan, leading researchers presented several studies that indicate simply being in the two Southwest Asian countries may be making servicemembers ill, a conclusion also drawn by an earlier Institute of Medicine (IoM) report.

The IoM committee cited the “high ambient concentrations of particulate matter generated by both human activities and natural sources” as a specific concern for military personnel who have served in Iraq and Afghanistan, saying the particulates “might be associated with long-term health effects,” including respiratory and cardiovascular effects and cancer.

Researchers say they are not surprised. Microparticles of toxic dust are ubiquitous in the two countries, said Navy Capt. Mark Lyles, DMD, PhD, chair of medical sciences and biotechnology at the Center for Naval Warfare Studies at the Naval War College in Newport, RI. His research indicates that “these particulates are inhabited by bacteria, fungi and viruses, as well as a variety of metals,” he reported during a presentation at the symposium at Stony Brook University School of Medicine in New York.

Something is clearly making military personnel ill, said Anthony Szema, MD, chief of the allergy section of the VA Medical Center in Northport, NY, and assistant professor of medicine and surgery at Stony Brook University. According to his research, 14% of medical visits in Iraq are due to respiratory complaints, which often do not resolve when servicemembers return home. In a retrospective study of 6,233 veterans who were discharged between March 2004 and May 2007 and were seen at the Northport VA Medical Center, he found that deployment to Iraq was associated with new-onset asthma (10%) at twice the rate of stateside troops (5%).

While not the entire problem, burn pits may be a contributor to health issues. As Szema noted, “burning anything leads to particulate matter (PM), which is inhaled and toxic to the lungs and heart.” Slow-burning, open-air pits release far more PM than high-temperature incinerators, he added.

Harsh environmental conditions also might contribute to the respiratory issues experienced by servicemembers. Conditions in Iraq “are unique and are dramatically different from the usual conditions that soldiers are exposed to in the U.S.,” Szema explained, adding that the region’s dry soil and dust-filled air contribute to the dust storms that occur 20 to 50 days per year and increase inhalation of particulates that can trigger asthma and other respiratory disorders.

High temperatures, low humidity and increased mouth-breathing associated with exercise also contribute to increased ingestion of fine particles, said retired Marine Capt. Richard Meehan, MD, chief of rheumatology at National Jewish Medical and Research Center in Denver. Meehan pointed out that particulate concentrations in Iraq exceeded safe levels established by the Environmental Protection Agency 84% percent of the time, as measured by the Army’s Center for Health Prevention and Promotion Medicine Deployment Environmental Surveillance program which found high concentrations of inhalable particulates smaller than 10 micrometers and respirable particulates smaller than 2.5 micrometers — sizes that can penetrate deep into the lungs and block terminal airways.

Dust storms, daily activities and even sand pick up these tiny particulates. “Environmental dust from the Iraqi [area] is ubiquitous and has the potential to be a source of pathogenic exposure,” Lyles said. More than 200 hemolytic and fungal isolates have been identified in dust in Iraq and Afghanistan, several of which show antibiotic resistance. In addition, 37 elements have been identified in particulates, including 15 bioactive metals including uranium, arsenic, chromium and lead.

Lyles also said that microbes in the dust of the region demonstrate an “exceptional ability to survive” in sterilization tests. He hypothesized that particulates composed of a porous silica core surrounded by clay serve as a protective coating and carrier for micro-organisms. As a result, the microbes are not killed when picked up in a storm and exposed to air and sunlight, as scientists previously assumed. Lyles also said that early animal studies suggest an association between dust exposure and long-term inflammation with mild to moderate eosinophilia.